package com.ruoyi.common.filter;

import com.ruoyi.common.utils.StringUtils;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 防止XSS攻击的过滤器
 *
 * @author ruoyi
 */
public class XssFilter implements Filter {
  /** 排除链接 */
  public List<String> excludes = new ArrayList<>();

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    String tempExcludes = filterConfig.getInitParameter("excludes");
    if (StringUtils.isNotEmpty(tempExcludes)) {
      String[] url = tempExcludes.split(",");
      for (int i = 0; url != null && i < url.length; i++) {
        excludes.add(url[i]);
      }
    }
  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest req = (HttpServletRequest) request;
    HttpServletResponse resp = (HttpServletResponse) response;
    if (handleExcludeURL(req, resp)) {
      chain.doFilter(request, response);
      return;
    }
    XssHttpServletRequestWrapper xssRequest =
        new XssHttpServletRequestWrapper((HttpServletRequest) request);
    chain.doFilter(xssRequest, response);
  }

  private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response) {
    String url = request.getServletPath();
    String method = request.getMethod();
    // GET DELETE 不过滤
    if (method == null || method.matches("GET") || method.matches("DELETE")) {
      return true;
    }
    return StringUtils.matches(url, excludes);
  }

  @Override
  public void destroy() {}
}
